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--- haas:spring2014:unix:projects:week4rev [2014/02/11 19:50] – created wedge
+++ haas:spring2014:unix:projects:week4rev [2014/02/14 22:00] (current) – [Review Topic] wedge
@@ Line 15: / Line 15: @@
 Instead of giving you some amazing new mind-blowing project to redefine your very life as we know it, I figured I'd instead give you a chance to take a quick breather and get in some review prior to resuming in full force.
+=====Review Topic=====
+For this week, the main topic of review will be file permissions. We see them when running an **ls -l**, for example:
+<cli>
+lab46:/usr/local/bin$ ls -l submit tclbiff
+-rwxr-xr-x  1 root   staff    115 Oct 14  2010 sshfix
+-rwxr-x---  1 wedge  lab46   4651 Jan 27 05:58 submit
+lab46:/usr/local/bin$
+</cli>
+Of course, the file permission part is:
+<code>
+    -rwxr-xr-x
+</code>
+We split this into 3 fields (the leftmost field is for file type) into user, group, and other.
+Breakdown is as follows:
+  * read <nowiki>(r)</nowiki> is 4
+  * write (w) is 2
+  * execute/search (x) is 1
+  * nothing (-) is 0
+In any given field, we add up the values, which will result in a value within the range 0-7.
+So, in our example above, broken down showing the component permissions:
+<code>
+               u      g      o
+          -   rwx    r-x    r-x
+      5      5
+</code>
+I wrote a tool for you to use in this project called **urev**.
+Your task will be to run this and complete 96 problems, in groups of 12 at a time (so you don't blow through them all in one sitting.. there's also a time delay before you can do the next set of 12-- so you clearly shouldn't wait until the last minute).
+To use urev, basically type in the 3 octal values matching the problem displayed (in the above example, you'd type in '7' '5' and '5', and upon pressing each one, it will appear on the screen.
+If you get all 3 correct, you'll earn a point. (Careful not to type too fast, otherwise the output may appear garbled).

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